What makes an aluminum drink can so strong?

An aluminum beverage can’s surprising strength comes primarily from its internal pressure, despite having walls that are only 75 microns thick. For sodas, the carbon dioxide creates a pressure of about 30 psi, which is twice the atmospheric pressure. For non-carbonated drinks like juice, nitrogen is added to create this pressure. This internal pressure pushes outward evenly, keeping the thin walls in a state of tension. While the walls have little strength in compression, they are very strong in tension, similar to a chain. This pressure makes the can strong enough to be stacked and even support the weight of an average adult. The can is designed to withstand pressures up to 90 psi, or six atmospheres, before buckling. The domed shape of the can’s bottom also contributes to its strength by distributing vertical loads, much like an arch.